London has been battered by 50mph winds that have felled trees and caused travel chaos. Powerful gusts swept across the capital as the Met Office issued a yellow "be aware" weather alert for most of the country.

Does Placido Domingo, the world's most renowned, prolific opera star, ever feel nervous before a performance? "Nervous?" he growls in a voice so rich that it seems to resonate through his whole huge body, and for a second I fear my question has insulted him.

But he smiles and answers lightly, with almost tremulous delicacy: "Always! There is not one day in my life that I have to perform that I'm not nervous."

Tomorrow he is giving a concert with Angela Gheorghiu at the O2 to 14,000 people. "I am very used to these concert venues of anything between eight and 15,000 people," he says - after all, he pioneered the very idea of pop-concert-sized classical performances in the early 1990s as one of The Three Tenors.

"And the sound is really appropriate to the venue, and the atmosphere is very nice. It's something I enjoy. But even so, I have to be very careful.

"I'm in London for a few days but apart from rehearsals I don't really feel like going out. The throat is very delicate. The violinist has his violin, the cellist has his cello, but we have an instrument that lives with us. It's affected by cold, it's affected by air conditioning. You can hear now my voice is not very clear today. It's very much affected by emotion, it's affected by news, by what you watch."

Does he mean international news bulletins? "Of course. They affect you always. This horrible thing in Norway has me completely shocked. I will never understand people that kill. For young people to lose their lives in this way should affect the whole world. It is one of the saddest stories I have heard."

The words are commonplace but he delivers them straight from the heart, with huge, resonant compassion. He is big enough, somehow, to channel and communicate heartache. It is the stuff opera is made of, after all.

The death of Amy Winehouse also grieves him. They never met but he is fully apprised of her talent.

"To lose an artist so young - it is terrible. I am so sad for her family, for her followers." His calm voice seems to offer comfort, like a benediction.

At 70, as well as performing new roles in a new register (he has started to sing baritone parts for the first time, to critical rapture) Domingo has become an elder statesman figure. He conducts, he runs an annual "Operalia" competition for young singers, and is general director of the LA Opera.

He also lends his gravitas further afield.

Earlier this month Fifa's president, Sepp Blatter, invited him and Henry Kissinger to join a "council of wisdom" to help restore the football governing body's battered reputation - a "surprise," concedes Domingo, telling a TV news interviewer yesterday: "I still have to find out what it means." Devoted to football, he says he still enjoys a kickabout. "I feel young!"

This week he also became chairman of the International Federation of the Phonographic Industry (IFPI) in order to help promote its work improving copyright legislation in a digital market-place. Music company heads such as Doug Morris, CEO of Sony, welcomed his appointment: "He is a distinguished artist who will be able to communicate the intrinsic value of music to decision-makers at the very highest level."

Domingo has always been a forward-thinking artist, devotedly popularising classical music since the 1990s, and he has recently been part of the technological revolution that sees opera broadcast via live satellite link-ups to thousands of people at once.

"Millions of people!" he corrects me. "Rigoletto [filmed last September in the streets of Mantua, where the opera is set] was seen by millions of people, direct, live. No replay." That must bring huge added pressures to performers? "OK, that's dangerous, yes, but if everything goes well it's fantastic."

Spanish-born, Domingo grew up in Mexico where both his parents were zarzuela singers. His first memory, "very vivid", is of seeing his parents dressing for the stage.

"My father in tails, my mother in a glamorous dress. Then immediately I saw them on the stage. I didn't know what it was but I knew it was something I loved."

Aged "maybe nine or 10", he would sit watching from the wings, "very quiet, but very happy. I also sometimes would sit with my father in the audience, and he would explain to me the orchestra, the scenery"

Domingo will perform zarzuela at the O2 concert tomorrow.

"It's music that has lived with me always. In zarzuela you have the dialogue, and then you start singing, so sometimes at home you start singing before you realise It happens to me now with two of my grandchildren. I start talking and they answer me singing, you know?"

Three of his eight grandchildren live in England.

"They are at school near the castle the castle which was burned not many years ago Yes, Windsor! They are three grandaughters, one 15, one 13, one 10. They all have a beautiful voice. I think they will become singers. I'm looking forward to having dinner with them tonight."

He thinks hamburgers at Bar Boulud is a good suggestion. "I really like almost every kind of food. I don't eat much," he says sadly, patting his stomach, "but I have my specialities: Mexican, Spanish, Chinese, Japanese and Lebanese."

Every now and then he likes a cigar; he goes to his family house in Acapulco to relax, although the demands of work rarely allow it. When he talks about "his four houses" he means Vienna, the Met, Covent Garden and La Scala.

Successfully treated for a cancerous colon polyp in March last year, he is more than fully recovered. His famous twinkle is definitely still there - he is gentle and decorous with everyone he meets, particularly ladies.

His pairing on Friday with the great beauty and diva Angela Gheorghiu will be perfect. Does she ever surprise him, on stage, with a new phrasing, or a particularly inspired legato?

"Collaborating is a wonderful thing. I remember with our Three Tenors concerts, we were collaborating so much but there were still moments when someone would come in with a beauooootiful phrase, and then the other wanted to improve it, and the next wanted to do something even better.

There is no dull moment when you are performing."

What distinguishes a London audience from others worldwide? "I love the London public. They are warm, they are respectful, and at the end of an opera where they contained themselves, they explode. Such an explosion it's unbelievable - 10 or 15 minutes' applause in London is the equivalent of maybe 40 minutes in Vienna. In Germany they never want to let you go, but in London they kind of say yes, we know the artist has to go."

And so, leaving me with two courteous, soft-bristled kisses, must the man himself.

Placido Domingo and Angela Gheorghiu are performing in concert together at The O2 tomorrow, July 29. Tickets are available from theo2.co.uk (0844 856 0202) and kililive.com